Arctic nearly free of summer sea ice during first half of 21st century

Apr 15, 2013

For scientists studying summer sea ice in the Arctic, it's not a question of "if" there will be nearly ice-free summers, but "when." And two scientists say that "when" is sooner than many thought—before 2050 and possibly within the next decade or two.

James Overland of NOAA's Pacific Marine Environmental Laboratory and Muyin Wang of the NOAA Joint Institute for the Study of Atmosphere and Ocean at the University of Washington, looked at three methods of predicting when the Arctic will be nearly ice free in the summer. The work was published recently online in the American Geophysical Union publication Geophysical Research Letters.

"Rapid Arctic sea ice loss is probably the most visible indicator of global climate change; it leads to shifts in ecosystems and economic access, and potentially impacts weather throughout the northern hemisphere," said Overland. "Increased physical understanding of rapid Arctic climate shifts and improved models are needed that give a more detailed picture and timing of what to expect so we can better prepare and adapt to such changes. Early loss of Arctic sea ice gives immediacy to the issue of climate change."

"There is no one perfect way to predict summer sea ice loss in the Arctic," said Wang. "So we looked at three approaches that result in widely different dates, but all three suggest nearly sea ice-free summers in the Arctic before the middle of this century."

Overland and Wang emphasized that the term "nearly" ice free is important as some sea ice is expected to remain north of the Canadian Archipelago and Greenland.

The "trendsetters" approach uses observed sea ice trends. These data show that the total amount of sea ice decreased rapidly over the previous decade. Using those trends, this approach extrapolates to a nearly sea ice-free Arctic by 2020.

The "stochasters" approach is based on assuming future multiple, but random in time, large sea ice loss events such as those that occurred in 2007 and 2012. This method estimates it would take several more events to reach a nearly sea ice-free state in the summer. Using the likelihood of such events, this approach suggests a nearly sea ice-free Arctic by about 2030 but with large uncertainty in timing.

The "modelers" approach is based on using the large collection of global climate model results to predict atmosphere, ocean, land, and sea ice conditions over time. These models show the earliest possible loss of sea ice to be around 2040 as greenhouse gas concentrations increase and the Arctic warms. But the median timing of sea ice loss in these models is closer to 2060. There are several reasons to consider that this median timing of sea ice loss in these models may be too slow.

"Some people may interpret this to mean that models are not useful. Quite the opposite," said Overland. "Models are based on chemical and physical climate processes and we need better models for the Arctic as the importance of that region continues to grow."

Taken together, the range among the multiple approaches still suggests that it is very likely that the timing for future sea ice loss will be within the first half of the 21st century, with a possibility of major loss within a decade or two.

Related Stories

Arctic sea ice has been declining over the past several decades as global climate has warmed. In fact, sea ice has declined more quickly than many models predicted, indicating that climate models may not be correctly representing ...

(PhysOrg.com) -- A nearly ice-free Arctic Ocean in the summer may happen three times sooner than scientists have estimated. New research says the Arctic might lose most of its ice cover in summer in as few ...

The Arctic sea ice is shrinking, both in extent and thickness. In addition to the manmade contribution to the sea ice loss, there are also natural factors contributing to this loss. In a new study from the ...

In the Arctic Ocean, the blanket of permanent sea ice is being progressively replaced by a transient winter cover. In recent years the extent of the northern ocean's ice cover has declined. The summer melt season is starting ...

Recommended for you

An analysis of buildings tagged red and yellow by structural engineers after the August 2014 earthquake in Napa links pre-1950 buildings and the underlying sedimentary basin to the greatest shaking damage, ...

As everyone who lives in the San Francisco Bay Area knows, the Earth moves under our feet. But what about the stresses that cause earthquakes? How much is known about them? Until now, our understanding of ...

(Phys.org)—A trio of researchers with the Indian Institute of Science has found, via computer simulation, that deforestation in one part of the world can impact rainfall patterns in another. In their paper ...

It's no surprise that Arctic sea ice is thinning. What is new is just how long, how steadily, and how much it has declined. University of Washington researchers compiled modern and historic measurements to ...

Reasearchers at the University of Cadiz have carried out a study that establishes the atmospheric conditions responsible for the generation of extreme meteorological events in the Gulf of Cadiz, which can ...

User comments : 12

NO mention is made of sea ice thickness or volume as contrasted with visible sea ice area coverage. This would make a big difference as a 10 meter thick, 100 sq km ice layer would take much longer to melt than a 2 meter thick, 100 sq km layer. From a satellite, or even a visual inspection on the surface, the sea ice area covered would appear the same.

I originally thought that as well, but the computer models should that about the eastern half to 2/3rds of the grain belt will actually get more precipitation. A recent model even showed half of Oklahoma, Kansas, and Nebraska getting more precipitation.

===LariAnn:

The thickness of the majority of the ice is known to within 10cm margin of error.

...the computer models should that about the eastern half to 2/3rds of the grain belt will actually get more precipitation. A recent model even showed half of Oklahoma, Kansas, and Nebraska getting more precipitation.

If so, then the question becomes: Will the additional energy and unsettled patterns due to global warming translate that greater precipitation into more extreme and frequent weather events which destroy crops and infrastructure due to more unseasonal and destructive storm precipitation (snow, heavy rain, hail, tornadoes, ice storms etc)? It may be a lose-lose situation where areas which get less precipitation may suffer drought as its own extreme weather event; while areas with increased precipitation may suffer from more unsettled/unseasonal extreme events which more than negate benefits from increased atmospheric moisture load due to global warming. Not so straightforward when more energy/moisture creates new drought/storm extremes/pattern. :)

Interesting how the denialist crowd mocks computer modelling when it suits them, but them uses often-misinterpreted computer models when it suits them.

Interesting how the AGW Alarmist Cult have a non-response when the "science" of their computer models is proven to be pure fabrications, all designed to propagate their agenda.

Anti:Like weather modelling decades ago, as bigger supercomputers come along and science gains more information to feed into them, then they will get better. Meteorology wasn't discredited by modelling back then, in that it's physics held up, it's really just empirical fluid dynamics + observations. Climate is that + the drivers/feedbacks. Made difficult by uncertainty in cycles such as ENSO. They can do no other than indicate a rise stuttered by pauses as these overlying cycles are modeled. However they may be 180 deg out from reality - that we see now. The general upward trend is not discredited by that. Just that the phasing is wrong.Cont

Modelers know full well their models are just one outcome of many possible. That's why ensemble forecasts are done, combining different models and "perturbed physics". This is to remove as much of the uncertainty as possible. BTW: You are free to post any peer-reviewed evidence of the "science proven to be pure fabrication" claim of yours. I am not aware of any. Please provide evidence of the driver of the current warming ( surely you're not obtuse enough to deny that ) that so perfectly mirrors the warming, and it's physical modelling also fits, ( bar pauses caused by SST cooling cycles, low solar irradiation and increased pollution from the Far East ). And on top of that the orbital parameters favour neutral or even slight cooling of the NH. if you continually look at things through the filter of conspiracy and politics you will always come across as paranoid. I know it helps to understand the atmosphere or even the way science works. Sadly many on here don't.

Please sign in to add a comment.
Registration is free, and takes less than a minute.
Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.

Javascript is currently disabled in your web browser. For full site functionality, it is necessary to enable Javascript.
In order to enable it, please see these instructions.